Indacaterol is chemically known as (R)-5-[2-(5,6-Diethylindan-2-ylamino)-1-hydroxyethyl]-8-hydroxy-1H-quinolin-2-one having the formula I as mentioned below:

Indacaterol is long acting inhaled β2-agonist marketed by Novartis under the trade name Arcapta Neohaler in US and Onbrez in Europe. Indacaterol is marketed as maleate salt. Indacaterol was first disclosed in the U.S. Pat. No. 6,878,721 (herein referred patent US'721). The process for Indacaterol maleate as described in the patent US'721 is depicted below:

The above process for preparing Indacaterol maleate comprises the step of reacting 8 substituted oxy-5-(R)-oxiranyl-(1H)-quinolin-2-one (III) with 2-amino-(5,6-diethyl)-indan (IV) to form an intermediate 5-[(R)-2-(5,6-diethyl-indan-2-ylamino)-1-hydroxy-ethyl]-8-substituted oxy-(1H)-quinolin-2-one (V). This reaction step is not regioselective, hence along with desired product 5-[(R)-2-(5,6-diethyl-indan-2-ylamino)-1-hydroxy-ethyl]-8-substituted-oxy-(1H)-quinolin-2-one, the below mentioned compounds are also formed as impurities.

Further, the above reaction mixture contains only about 60% to 80% of desired compound i.e. 5-[(R)-2-(5,6-diethyl-indan-2-ylamino)-1-hydroxy-ethyl]-8-substituted oxy-(1H)-quinolin-2-one. The purification of this intermediate is done using silica gel chromatography which is tedious and requires large amount of solvents and is not suitable for industrial synthesis.
The U.S. Pat. No. 7,534,890 discloses a process that avoids the column purification by the formation of acid addition salts of intermediate (formula-IV). The processes for preparation Indacaterol or its pharmaceutically acceptable salts are also disclosed in WO2000075114, WO20050123684, WO2008093188 and WO2004087668.
It is observed that prior art processes are complicated, costly and not suitable for large scale industrial preparation therefore, there exists a need to develop a novel economically significant process for the preparation of Indacaterol or its pharmaceutically acceptable salts for large scale preparation.